<div class="layui-form-item">
    <label class="layui-form-label">金币:</label>
    <div class="layui-input-block">
        <input type="text" onkeyup="SetSum()" name="bill_gold" lay-verify="title" autocomplete="off" placeholder="请输入金币量" class="layui-input">
    </div>
</div>

<div class="layui-form-item">
    <label class="layui-form-label">金额:</label>
    <div class="layui-input-block">
        <input style="color: red;width: 100px;border: 0" type="text" name="bill_sum" lay-verify="title" class="layui-input" disabled>
    </div>
</div>